// Problem: 
// Contest: 
// URL: 
// Memory Limit: 
// Time Limit: 
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#include<bits/stdc++.h>
using namespace std;
#define int long long
inline int read(){
	int s=0,w=1;
	char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}
	while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar();
	return s*w;
}
int N=1e9+7;
int qpow(int x,int n)
{
    int ret=1;
    while(n)
    {
        if(n&1)ret=ret*x%N;
        x=x*x%N;
        n>>=1;
    }
    return ret; 
}
signed main()
{
	int T=1;
//	cin>>T;
	while(T--)  
	{
		int n,ans=0;
		cin>>n;
		vector<int> v(n+1),dp(n+1);
		for(int i=1;i<n;i++)
		{
			cin>>v[i];
			dp[i]=dp[i-1]^v[i];
            ans=(ans+(2*dp[i]*qpow(3, n-i-1))%N)%N;
            //cout<<ans<<endl;
		}
        cin>>v[n];
		cout<<(ans+(dp[n-1]^v[n]))%N<<endl;
	}
	return 0;
}